This episode's headline: Tax Reform: Republicans vs. Democrats; Raising the Ante on Toxic Clean Up; World's Fair: Unfair to New Orleans?; Watching the Games. The guests include In Washington: Sen. ROBERT KASTEN, Republican, Wisconsin; Rep. RICHARD GEPHARDT, Democrat, Missouri; Rep. JAMES FLORIO, Democrat, New Jersey; In New York: EDWIN HOLMER, Chemical Manufacturers Association; In New Orleans: GERALDINE BELL, Community Activist; MIKE VALENTINO, New Orleans Hotel and Motel Owners Association. Byline: In New York: ROBERT MacNEIL, Executive Editor; In Washington: JIM LEHRER, Associate Editor; JUDY WOODRUFF, Correspondent; Reports from NewsHour Correspondents: JACK CRAIG (Boston Globe), in Boston