Tony Dow, the smiling, straight-arrow Wally Cleaver from "Leave It to Beaver, says he has battled depression for 20 years. Dow, now 44 and co-star of "The New Leave It to Beaver," was in Venice, Fla., as a spokesman for the National Institute of Mental Health's DART program - Depression Awareness, Recognition and Treatment. He said he suffered his first of two major bouts with depression about eight years after the original "Beaver" ended. "One morning I just didn't get out of bed," Dow said. "A lot of people have the same situation but don't get help. It was a new experience to see other people in the same boat." Dow says he overcame the problem with treatment and family love and now, through a balanced diet and exercise, he has quit taking anti-depression drugs.