CREATE TABLE table_203_497 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

who has won the most bronze medals ?
SELECT "nation" FROM table_203_497 ORDER BY "bronze" DESC LIMIT 1
SELECT "nation" FROM "table_203_497" ORDER BY "bronze" DESC NULLS LAST LIMIT 1