CREATE TABLE table_203_172 (id DECIMAL, "title" TEXT, "date of creation" TEXT, "surname" TEXT, "first titular" TEXT)

which duke has the same date of creation as the duke of coimbra ?
SELECT "title" FROM table_203_172 WHERE "title" <> 'duke of coimbra' AND "date of creation" = (SELECT "date of creation" FROM table_203_172 WHERE "title" = 'duke of coimbra')
SELECT "title" FROM "table_203_172" WHERE "date of creation" = (SELECT "date of creation" FROM "table_203_172" WHERE "title" = 'duke of coimbra') AND "title" <> 'duke of coimbra'