CREATE TABLE table_3819 ("No. in series" CLOB, "No. in season" CLOB, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Production code" CLOB, "U.S. viewers  ( millions ) " CLOB)

When there are 5.2 million u.s. viewers how many numbers in series are there?
SELECT COUNT("No. in series") FROM table_3819 WHERE "U.S. viewers (millions)" = '5.2'
SELECT COUNT("No. in series") FROM "table_3819" WHERE "U.S. viewers (millions)" = '5.2'