CREATE TABLE table_203_61 (id DECIMAL, "rank" DECIMAL, "nation" TEXT, "gold" DECIMAL, "silver" DECIMAL, "bronze" DECIMAL, "total" DECIMAL)

which african country had 8 silver medal wins , but no gold medals ?
SELECT "nation" FROM table_203_61 WHERE "silver" = 8 AND "gold" = 0
SELECT "nation" FROM "table_203_61" WHERE "gold" = 0 AND "silver" = 8