Sunday's AFC Championship game between the Baltimore Ravens and he New England Patriots may scored solidly in the ratings nationally. (With 41.5 million viewers, according to preliminary Nielsen figures, it was the highest-rated program since last year's Super Bowl, but it was down from the NFC Championship game that aired in the comparable time period a year ago.) However, the national ratings were like nothing compared with those in Baltimore where the game scored a whopping 51.8 household rating and attracted 71 percent of the city's viewers. Final ratings, national and local, have been delayed because of the Martin Luther King Jr. holiday. The game was carried by CBS-owned WJZ-TV, which will also carry the Super Bowl on Feb. 3.