CREATE TABLE table_204_568 (id NUMBER, "pennant" CLOB, "name" CLOB, "hull builder" CLOB, "ordered" CLOB, "laid down" CLOB, "launched" CLOB, "accepted into service" CLOB, "commissioned" CLOB, "est. building cost" CLOB, "fate" CLOB)

how many ships were built after ardent ?
SELECT COUNT(*) FROM table_204_568 WHERE "commissioned" > (SELECT "commissioned" FROM table_204_568 WHERE "name" = 'ardent')
SELECT COUNT(*) FROM "table_204_568" WHERE "commissioned" > (SELECT "commissioned" FROM "table_204_568" WHERE "name" = 'ardent')