user: Question: How many winning drivers were there in the race that had a fastest lap time of 56.920?
Columns: ['Rd', 'Name', 'Pole Position', 'Fastest Lap', 'Winning driver', 'Winning team', 'Report']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'Kraco Dixie 200', 'Rick Mears', '26.730', 'Gordon Johncock', 'Patrick Racing', 'Report']
SQL:

assistant: SELECT COUNT("Winning driver") FROM "Table" WHERE "Fastest Lap" = '56.920';