CREATE TABLE table_204_183 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

who is the top ranked nation ?
SELECT "nation" FROM table_204_183 ORDER BY "rank" LIMIT 1
SELECT "nation" FROM "table_204_183" ORDER BY "rank" NULLS FIRST LIMIT 1