CREATE TABLE table_19530 ("No. in series" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Production code" CLOB)

When did the show directed by Michael Dimartino first air?
SELECT "Original air date" FROM table_19530 WHERE "Directed by" = 'Michael DiMartino'
SELECT "Original air date" FROM "table_19530" WHERE "Directed by" = 'Michael DiMartino'