user: Question: What is the earliest year that has a Bristol engine?
Columns: ['Year', 'Entrant', 'Chassis', 'Engine', 'Points']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1950.0, 'Bob Gerard', 'ERA B-type', 'ERA', 0.0]
SQL:

assistant: SELECT MIN("Year") FROM "Table" WHERE "Engine" = 'Bristol';