CREATE TABLE table_72108 ("Rd" FLOAT, "Name" TEXT, "Pole Position" TEXT, "Fastest Lap" TEXT, "Winning driver" TEXT, "Winning team" TEXT, "Report" TEXT)

How many winning drivers were there in the race that had a fastest lap time of 56.920?
SELECT COUNT("Winning driver") FROM table_72108 WHERE "Fastest Lap" = '56.920'
SELECT COUNT("Winning driver") FROM "table_72108" WHERE "Fastest Lap" = '56.920'