What was the sum of the years, when the entrant was Scuderia Centro Sud, and when there were 6 points?
CREATE TABLE table_71425 (
    "Year" real,
    "Entrant" text,
    "Chassis" text,
    "Engine" text,
    "Points" real
)
SELECT SUM("Year") FROM table_71425 WHERE "Entrant" = 'scuderia centro sud' AND "Points" = '6'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What was the sum of the years, when the entrant was Scuderia Centro Sud, and when there were 6 points? ### Input: CREATE TABLE table_71425 (
    "Year" real,
    "Entrant" text,
    "Chassis" text,
    "Engine" text,
    "Points" real
) ### Response: SELECT SUM("Year") FROM table_71425 WHERE "Entrant" = 'scuderia centro sud' AND "Points" = '6'