Question: Which film has the director who is older than the other, Calling Bulldog Drummond or Convoy (1978 Film)? 
Sentence (from "Calling Bulldog Drummond"): Calling Bulldog Drummond is a 1951 British crime film directed by Victor Saville and featuring Walter Pidgeon, Margaret Leighton, Robert Beatty, David Tomlinson and Bernard Lee.
Relevant evidence: Yes