CREATE TABLE table_204_630 (id DECIMAL, "no" DECIMAL, "date" TEXT, "race" TEXT, "track" TEXT, "winner" TEXT, "reports" TEXT)

who won the most ?
SELECT "winner" FROM table_204_630 GROUP BY "winner" ORDER BY COUNT(*) DESC LIMIT 1
SELECT "winner" FROM "table_204_630" GROUP BY "winner" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 1