TV RATINGS : Mid-Season Replacements Debut Strongly

Buoyed by the return to form of its few big prime-time shows (“60 Minutes”) and the completion of the Winter Olympics, CBS climbed back into second place (after leader NBC) for the week ending March 20, according to the A.C. Nielsen Co.’s ratings, released Tuesday. But the emergence of such new mid-season replacement series as “In the Heat of the Night” (which are dubbed “designated hitters” by NBC’s Brandon Tartikoff) gave the week once again to NBC. The CBS Evening News was No. 1 among newscasts, though, with NBC’s Tom Brokaw finishing third behind Dan Rather and ABC’s Peter Jennings. (A complete ratings list appears on page 10.)

* ABC’s new “Wonder Years”--a nostalgic look at teens in the early 1960s--proved to be the strongest new entry, taking the No. 7 spot for the week. Also, the show’s Tuesday night lead-in--”Who’s the Boss?”--and its follow-up, “Moonlighting,” don’t hurt its chances, either.

Show Points Share Week 1. The Cosby Show 28.2 43 3/20 (NBC) 2. A Different World 25.2 39 3/20 (NBC) (repeat) 3. 60 Minutes (tie) 22.5 38 3/20 (CBS) 3. Golden Girls (tie) 22.5 38 3/20 (NBC) 5. Who’s The Boss? 22.3 34 3/20 (ABC) * Wonder Years 21.4 32 3/20 (ABC) (premiere episode)