Here is a comparison of key parts of rival deficit-reduction plans backed by House Democrats and the Senate Finance Committee:

GASOLINE: No change in the House bill. The Senate would raise the 9-cent tax to 18 1/2 cents a gallon by 1992. Neither bill would affect heating oil.INDEXING: The House would forgo for one year the annual adjustments to income tax brackets and personal exemptions, which are designed to protect against inflation-caused bracket creep. That would mean higher income taxes for everybody in 1991. The Senate has no such provision.

ALCOHOL: House - Raise the $12.50-a-gallon tax on 100-proof liquor by $1; double the beer tax to 32 cents a six-pack; raise taxes on most wines, including table wine, which would go from 3 cents a 750-milliliter bottle to 25 cents. Senate - Raise liquor tax by $1.20; double beer tax; raise wine tax to 21 cents.

TOBACCO: Both would raise the 16-cent cigarette tax by 4 cents in 1991 and another 4 cents in 1993. Snuff, cigars and other tobacco would face 25 percent tax increases each year.

FLYING: Both would raise the 8 percent tax on airline tickets to 10 percent.

LUXURIES: Both would impose a 10 percent tax on the portion of the price of cars above $30,000; boats above $100,000; jewelry above $5,000; furs above $10,000 (House) or $5,000 (Senate), and private planes $100,000 (House) or $250,000 (Senate).

TAX RATES: The House bill would raise the top rate paid by the wealthiest people, now 28 percent, to 33 percent. It would impose a 10 percent surtax on those with taxable incomes over $1 million. The Senate bill would do neither.

ITEMIZED DEDUCTIONS: The Senate would limit itemized deductions (except those for medical expenses and investment interest) of people with adjusted gross income over $100,000. Only 95 percent of deductions would be allowed against the portion of income above $100,000.

CAPITAL GAINS: The House bill would allow a person to avoid tax on half of up to $200,000 of capital gains earned in a lifetime; the gains could come from most investments but not from stocks. A person with annual income under $100,000 could avoid tax on another $1,000 a year of gains, including those on the sale of stock. No capital gain would be taxed at a rate above 28 percent. The Senate bill has no capital-gains provisions.

LOW-INCOME: Both bills would increase the earned-income tax credit, which benefits low-income families with children, as a way of offsetting some of the increased excise taxes. The House plan included an $11 billion, five-year expansion of the credit; the Senate, $16.8 billion.

MEDICARE TAXES: House would increase to $100,000 the maximum annual wage to which the 1.45 percent Medicare tax applies. The tax is withheld as part of the Social Security tax. The Senate would raise the limit to $89,000. The Senate would require all state and local government workers and their employers to pay the tax; the House would continue exempting workers hired before 1986.

MEDICARE PREMIUMS: House would raise the $28.60 monthly premium for Medicare Part B insurance to $29.90 next year and $46.20 by 1995. Senate: $29.90 next year and $47 by 1995.

MEDICARE DEDUCTIBLE: House would raise to $100 through 1995 the present $75 deductible, which beneficiaries must pay before Medicare starts paying for doctor bills. Senate: $150 each year.

SOCIAL SECURITY: Both would require all state and local government workers not covered by a public retirement plan to pay Social Security taxes.