CREATE TABLE table_29035 ("Series #" FLOAT, "Episode #" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "U.S. viewers  ( millions ) " CLOB)

Which series # had 0.645 U.S. viewers(millions)?
SELECT MAX("Series #") FROM table_29035 WHERE "U.S. viewers (millions)" = '0.645'
SELECT MAX("Series #") FROM "table_29035" WHERE "U.S. viewers (millions)" = '0.645'