FIRST OFF . . .

The experiments and the waiting are finally over. It’s funny man Jay Leno who will be the “official and exclusive designated hitter” for Johnny Carson on “The Tonight Show,” NBC announced Tuesday. Leno’s contract as guest host for the 1988-89 season was announced, and there will be no competition from Garry Shandling, who will be working for the “rival” Fox Broadcasting Co. And what was Carson’s official comment on Leno’s signing? “Besides being extremely talented, Mr. Leno owns several motorcycles, which solves the transportation problem in case his car breaks down.”