user: Question: What was the surface during Wimbledon in 1974?
Columns: ['Outcome', 'Year', 'Championship', 'Surface', 'Partner', 'Opponents', 'Score']
Types: ['text', 'real', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Winner', 1971.0, 'Australian Open', 'Grass', 'Margaret Court', 'Joy Emerson Lesley Hunt', '6–0, 6–0']
SQL:

assistant: SELECT "Surface" FROM "Table" WHERE "Championship" = 'Wimbledon' AND "Year" = 1974.0;