user: Question: What was the sum of the years, when the entrant was Scuderia Centro Sud, and when there were 6 points?
Columns: ['Year', 'Entrant', 'Chassis', 'Engine', 'Points']
Types: ['real', 'text', 'text', 'text', 'real']
Sample row: [1961.0, 'Scuderia Centro Sud', 'Cooper T53', 'Maserati Straight-4', 0.0]
SQL:

assistant: SELECT SUM("Year") FROM "Table" WHERE "Entrant" = 'Scuderia Centro Sud' AND "Points" = 6.0;