Possible Clues:

• Jim ___, one-handed Yankee who pitched a no-hitter in 1993
• Half the "Who's on First?" team
• PM Sir John and actor Roger___
• Costello's film partner
• -- and Costello, American vaudeville act
• Half of the "Who's on First?" team
• Half of an old comedy team
• Religious leader said to be one of a comic duo
• — and Costello
• 'Who's on first' speaker