CREATE TABLE table_203_653 (id NUMBER, "rank" NUMBER, "nation" CLOB, "gold" NUMBER, "silver" NUMBER, "bronze" NUMBER, "total" NUMBER)

the average silver medal count of the first five ranked nations ?
SELECT AVG("silver") FROM table_203_653 WHERE "rank" <= 5
SELECT AVG("silver") FROM "table_203_653" WHERE "rank" <= 5