CREATE TABLE table_29521 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "U.S. viewers  ( millions ) " CLOB)

List the series number for season 12.
SELECT COUNT("No. in series") FROM table_29521 WHERE "No. in season" = '12'
SELECT COUNT("No. in series") FROM "table_29521" WHERE "No. in season" = '12'