user: Question: What year was there a Lotus 25 Chassis?
Columns: ['Year', 'Entrant', 'Chassis', 'Engine', 'Points']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1963.0, 'Ecurie Maarsbergen', 'Porsche 718', 'Porsche Flat-4', 3.0]
SQL:

assistant: SELECT "Year" FROM "Table" WHERE "Chassis" = 'Lotus 25';