user: Question: How many wins did the 500cc class have in 1979?
Columns: ['Year', 'Class', 'Team', 'Points', 'Rank', 'Wins']
Types: ['real', 'text', 'text', 'real', 'text', 'real']
Sample row: [1974.0, '250cc', 'Yamaha', 10.0, '19th', 0.0]
SQL:

assistant: SELECT "Wins" FROM "Table" WHERE "Class" = '500cc' AND "Year" = 1979.0;