WORTH NOTING ON TV

* WEDNESDAY

20th Century (A&E, 10-11 p.m.): Lately TV has been making a point of taking ''real-life'' looks at the subjects of popular movies - Pocahontas, for instance, was the focus of a recent documentary that contrasted her life with Disney's cinematic version.

This edition of the documentary series, hosted by Mike Wallace, deals with the tense moments when United States astronauts James Lovell, Fred Haise, and John Swigert were literally lost in space during the 1970 Apollo 13 mission. The huge hit film based on this same subject, of course, is director Ron Howard's ''Apollo 13,'' starring Tom Hanks and Kevin Bacon.

The TV program chronicles the explosion of an oxygen tank as the spacecraft nears the moon. Viewers hear the anxious voices of the crew and the tense back-and-forth with mission control as ultimately successful emergency steps are improvised.

* THURSDAY

Newt Raw (MTV, 10-10:30 p.m.): Before the title gives you the wrong idea, let it be quickly noted that ''Newt Raw'' is simply MTV News's way of saying that the interview with Speaker of the House Newt Gingrich is unedited, in the tradition of the channel's ''Raw'' series.

Speaker Gingrich will be asked unadorned questions by a group of 18-to-24-year-olds in a forum to be taped Thursday and aired that day.

* SUNDAY

Convict Cowboy (Showtime. 8-9:45 p.m.): Oscar-winner Jon Voigt stars as Ry, a professional rodeo cowboy serving a life sentence on a Montana prison-ranch, in this often-explicit made-for-Showtime production.

When a young cowboy (Kyle Chandler) is sent to the prison for two years, a hard-won friendship between Ry and the younger man evolves, as Ry teaches him the ropes - no pun intended. The relationship is tested and proven during a tense confrontation that climaxes the action.

Please check local listings for these programs.