CREATE TABLE table_204_302 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

which is the only nation to win a gold medal and nothing else ?
SELECT "nation" FROM table_204_302 WHERE "gold" = 1 AND "silver" = 0 AND "bronze" = 0
SELECT "nation" FROM "table_204_302" WHERE "bronze" = 0 AND "gold" = 1 AND "silver" = 0