CREATE TABLE table_51496 ("Rank" FLOAT, "Engine" TEXT, "Wins" FLOAT, "First win" TEXT, "Latest win" TEXT)

What is the rank 6 lowest win who's first win was at the 1950 British Grand Prix?
SELECT MIN("Wins") FROM table_51496 WHERE "Rank" > '6' AND "First win" = '1950 british grand prix'
SELECT MIN("Wins") FROM "table_51496" WHERE "First win" = '1950 british grand prix' AND "Rank" > '6'