CREATE TABLE table_203_61 (id NUMBER, "rank" NUMBER, "nation" CLOB, "gold" NUMBER, "silver" NUMBER, "bronze" NUMBER, "total" NUMBER)

what is the difference of silver medals between south africa and kenya ?
SELECT (SELECT "silver" FROM table_203_61 WHERE "nation" = 'south africa') - (SELECT "silver" FROM table_203_61 WHERE "nation" = 'kenya')
SELECT (SELECT "silver" FROM "table_203_61" WHERE "nation" = 'south africa') - (SELECT "silver" FROM "table_203_61" WHERE "nation" = 'kenya')