CREATE TABLE table_203_559 (id NUMBER, "no." NUMBER, "name" CLOB, "took office" CLOB, "left office" CLOB, "president served under" CLOB, "notable for" CLOB)

how many commissioners have there been ?
SELECT COUNT(DISTINCT "no.") FROM table_203_559
SELECT COUNT(DISTINCT "no.") FROM "table_203_559"