CREATE TABLE table_16330 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Production code" CLOB, "U.S. viewers  ( millions ) " CLOB)

What episode number had production code e4423?
SELECT MAX("No. in season") FROM table_16330 WHERE "Production code" = 'E4423'
SELECT MAX("No. in season") FROM "table_16330" WHERE "Production code" = 'E4423'