CREATE TABLE table_26198709_1 (rank__week_ INT, production_code VARCHAR)

What is the weeks rank for the episode with the production code 1alf05?
SELECT MAX(rank__week_) FROM table_26198709_1 WHERE production_code = "1ALF05"
SELECT MAX("rank__week_") FROM "table_26198709_1" WHERE "1ALF05" = "production_code"