Three-term Alabama Sen. Howell Heflin said he would not seek re-election next year, bringing to four the number of Senate Democrats who plan to retire. In a speech on the Senate floor, the 73-year-old former chief justice of the Alabama supreme court, who has suffered from a series of medical problems, said "the time to pass the torch to another generation is near." Heflin's decision makes it tougher for Democrats to strengthen their 54-46 Senate minority in the 1996 elections (Alabama is now largely Republican). At least three Democrats -- Sens. Sam Nunn of Georgia, Claiborne Pell of Rhode Island, and David Pryor of Arkansas -- may join the retirement list.