WORTH NOTING ON TV

FRIDAY

Candidates' Debate (PBS, 9-11 p.m., E.T.): The TV networks have agreed that each one will sponsor a debate among the major candidates for the Democratic presidential nomination, and it's PBS's turn. This live round table from Washington is being produced by "NewsHour" and moderated by its anchors: Robert MacNeil and Jim Lehrer. SUNDAY

O Pioneers (CBS, 9-11 p.m.): A dramatization of Willa Cather's enduring 1913 novel of prairie life is the vehicle for Jessica Lange's first made-for-TV movie. She plays a second-generation Swedish-American who preserves and uplifts a turn-of-the-century Nebraska homestead - a suitably challenging role for an actor whose talent transcends the glamour she was originally known for. Filmed on location in Nebraska, this production marks a noteworthy 172 shows for the Hallmark Hall of Fame - TV's longest-runni ng venue for dramatic specials, here beginning its 42nd season.

Legacy (PBS, 8-10 p.m.): No less than civilization itself is the ultimate subject of this British series. Michael Wood - the articulate host of "In Search of the Trojan War" and "Art in the Western World explores the past, present, and possible future direction of Iraq, India, China, Egypt, Central America, and the West. He travels to dozens of spots and deals with a myriad of detail, looking for the large questions of life asked and answered by each of these civilizations. The series was created as six programs, but is packaged here in two-show episodes aired over three consecutive nights. This opener considers both Iraq and India.

Please check local listings for all programs, especially those on PBS.