CREATE TABLE table_31146 ("No. in series" FLOAT, "No. in season" FLOAT, "Title" CLOB, "Directed by" CLOB, "Written by" CLOB, "Original air date" CLOB, "Production code" FLOAT)

What date did episode 4 in the season originally air?
SELECT "Original air date" FROM table_31146 WHERE "No. in season" = '4'
SELECT "Original air date" FROM "table_31146" WHERE "No. in season" = '4'