CREATE TABLE table_3515 ("Episode #" CLOB, "Season Episode #" CLOB, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Prod. code" CLOB)

What is the production code for episode #78?
SELECT "Prod. code" FROM table_3515 WHERE "Episode #" = '78'
SELECT "Prod. code" FROM "table_3515" WHERE "Episode #" = '78'