CREATE TABLE table_name_31 (district VARCHAR2, first_elected VARCHAR2, incumbent VARCHAR2)

Which District has a First Elected of 1904 and an Incumbent of Duncan E. Mckinlay?
SELECT district FROM table_name_31 WHERE first_elected = 1904 AND incumbent = "duncan e. mckinlay"
SELECT "district" FROM "table_name_31" WHERE "duncan e. mckinlay" = "incumbent" AND "first_elected" = 1904