CREATE TABLE table_31909 ("Round" FLOAT, "Circuit" TEXT, "Date" TEXT, "Pole Position" TEXT, "Fastest Lap" TEXT, "Winning Driver" TEXT, "Winning Team" TEXT)

Name the winning driver for round 7
SELECT "Winning Driver" FROM table_31909 WHERE "Round" = '7'
SELECT "Winning Driver" FROM "table_31909" WHERE "Round" = '7'