This episode's headline: Looking Ahead; No More Tests?; Final Sale. The guests include In Washington: Amb. LYNN HANSEN, U.S. Arms Control Agency; EVGENI VELIKHOV, Soviet Academy of Sciences; In Columbus, Ohio: Lt. Gov. PAUL LEONARD, Lt. Gov. of Ohio; RAY MILLER, Ohio State Representative; REPORTS FROM NEWSHOUR CORRESPONDENTS: ELIZABETH BRACKETT; JEFFREY KAYE, KCET, Los Angeles; JIM FISHER. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor