user: Question: What's the engine used for rounds 5-6?
Columns: ['Constructor', 'Chassis', 'Engine', 'Tyres', 'Driver', 'Rounds']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Lotus - Ford', '79 80', 'Ford Cosworth DFV 3.0 V8', 'G', 'Mario Andretti', 'All']
SQL:

assistant: SELECT "Engine" FROM "Table" WHERE "Rounds" = '5-6';