CREATE TABLE table_204_311 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

which nations had a gold medal but no silver medals ?
SELECT "nation" FROM table_204_311 WHERE "gold" = 1 AND "silver" = 0
SELECT "nation" FROM "table_204_311" WHERE "gold" = 1 AND "silver" = 0