CREATE TABLE table_56431 ("Episode #" TEXT, "Title" TEXT, "Directed by" TEXT, "Written by" TEXT, "Original airdate" TEXT)

What is the episode # of the episode that aired on April 5, 1998?
SELECT "Episode #" FROM table_56431 WHERE "Original airdate" = 'april 5, 1998'
SELECT "Episode #" FROM "table_56431" WHERE "Original airdate" = 'april 5, 1998'