user: Question: Who was the constructor for a FW20 chassis?
Columns: ['Entrant', 'Constructor', 'Chassis', 'Engine †', 'Tyre', 'Driver', 'Rounds']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Winfield Williams', 'Williams - Mecachrome', 'FW20', 'Mecachrome GC37-01', 'G', 'Jacques Villeneuve', 'All']
SQL:

assistant: SELECT "Constructor" FROM "Table" WHERE "Chassis" = 'FW20';