CREATE TABLE table_21146729_6 (director VARCHAR, writer_s_ VARCHAR)
SELECT director FROM table_21146729_6 WHERE writer_s_ = "John W. Bloch"
ใครคือผู้กำกับเมื่อผู้เขียนคือ John W. Bloch
Who was the director when the writer(s) was John W. Bloch?