user: ### NOW ANSWER:
Question: D'Oyly Carte 1939 Tour of Richard Walker involves what D'Oyly Carte 1945 Tour?
Columns: ['Role', "D'Oyly Carte 1920 Tour", "D'Oyly Carte 1930 Tour", "D'Oyly Carte 1939 Tour", "D'Oyly Carte 1945 Tour", "D'Oyly Carte 1950 Tour"]
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Lieutenant', 'Sydney Granville', 'Joseph Griffin', 'Leslie Rands', 'Leslie Rands', 'Donald Harris']
SQL:

assistant: SELECT "D'Oyly Carte 1945 Tour" FROM "Table" WHERE "D'Oyly Carte 1939 Tour" = 'Richard Walker';