CREATE TABLE table_203_408 (id NUMBER, "rd." NUMBER, "grand prix" CLOB, "date" CLOB, "location" CLOB, "pole position" CLOB, "fastest lap" CLOB, "winning driver" CLOB, "constructor" CLOB, "report" CLOB)

what is the total number of rounds ?
SELECT COUNT(DISTINCT "rd.") FROM table_203_408
SELECT COUNT(DISTINCT "rd.") FROM "table_203_408"