Michael Dukakis would edge Vice President George Bush if the presidential election were held now, provided black civil rights leader Jesse Jackson was not his running mate, a new poll said on Friday.

A survey by USA Today and Cable News Network gave the Massachusetts governor, the likely Democratic nominee, a 45-43 percent lead over Bush. But the poll said Bush would defeat a Dukakis-Jackson ticket by 49-42 percent.One of the major questions in the campaign is whether Jackson will demand the vice presidential nomination. Party leaders fear that black bias will hurt Democratic prospects if Jackson is on the ticket.

But Jackson campaign manager Gerald Austin says his candidate has earned the spot by capturing the second largest group of nominating delegates.

Jackson himself says that the choice of a running mate is the perogative of the presidential nominee and Dukakis said on Thursday: "If I were to finish second, it wouldn't entitle me to anything more than consideration, period."

The two men stumped in Pennsylvania and Ohio on Friday in what they vowed would be a harmonious competition in the remaining primary contests.

They square off in their first one-on-one debate of the campaign in Philadelphia on Friday night. But with both men pledging Dukakis's words to "emphasize our strengths, not the other guy's weaknesses," it should be a polite affair.

Dukakis seems set for a big victory in Pennsylvania, where 178 Democratic convention delegates are at stake next Tuesday.

Blacks account for just 15 percent of Pennsylvania's Democratic vote. Jackson won just 16 percent of the state's vote in his 1984 race for the Democratic nomination, almost all of which came from Philadelphia's black neighborhoods.

Several surveys say Dukakis leads Jackson by more than 30 points in Pennsylvania and it appears the Massachusetts governor could win 140 or more of the state's delegates.

Dukakis leads Jackson 1,065-859 in the race for the 2,082 delegates needed to win the Democratic nomination, according to NBC estimates.

Most political strategists say Dukakis is likely to win all of the remaining primary contests. Jackson aides say their candidate's best remaining chance to win a pre-election contest is in California, the final and largest primary, on June 7.

And more and more, Jackson and his aides are emphasizing their success in influencing the party rather than winning its presidential nomination.