CREATE TABLE table_23242933_2 (no_in_series NUMBER, written_by VARCHAR2)

What's the series number of the episode written by Dan Vebber?
SELECT MAX(no_in_series) FROM table_23242933_2 WHERE written_by = "Dan Vebber"
SELECT MAX("no_in_series") FROM "table_23242933_2" WHERE "Dan Vebber" = "written_by"