user: Question: Count the average Wins which has a Class of 250cc, and a Year of 1972?
Columns: ['Year', 'Class', 'Team', 'Points', 'Wins']
Types: ['real', 'text', 'text', 'real', 'real']
Sample row: [1970.0, '250cc', 'Yamaha', 0.0, 0.0]
SQL:

assistant: SELECT AVG("Wins") FROM "Table" WHERE "Class" = '250cc' AND "Year" = 1972.0;