CREATE TABLE table_17623902_1 (original_air_date VARCHAR, written_by VARCHAR)

What was the original air date of this episode that was written by Debbie Sarjeant?
SELECT original_air_date FROM table_17623902_1 WHERE written_by = "Debbie Sarjeant"
SELECT "original_air_date" FROM "table_17623902_1" WHERE "Debbie Sarjeant" = "written_by"