user: Question: Tell me the constructor for Alberto Colombo and chassis of A1
Columns: ['Entrant', 'Constructor', 'Chassis', 'Engine', 'Tyres', 'Driver', 'Rounds']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Parmalat Racing Team', 'Brabham - Alfa Romeo', 'BT45C BT46 BT46B BT46C', 'Alfa Romeo 115-12 3.0 F12', 'G', 'Niki Lauda', 'All']
SQL:

assistant: SELECT "Constructor" FROM "Table" WHERE "Driver" = 'Alberto Colombo' AND "Chassis" = 'A1';