CREATE TABLE table_21746 ("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)

How many writers are listed for the episode with a production code of 5008?
SELECT COUNT("Written by") FROM table_21746 WHERE "Production code" = '5008'
SELECT COUNT("Written by") FROM "table_21746" WHERE "Production code" = '5008'