what is creon definition of an effective ruler?

I don't think he was an effective ruler. Creon is portrayed as controlling and domineering, insensitive to the feeling and will of anyone who doesn’t share his near-fanatical belief in the authority and power of law. He is an autocrat and a dictator, something of a tyrant, refusing to allow any sort of love or compassion temper and/or challenge his absolute belief in his absolute power. By the end of the play, however, circumstances have brought about a change of heart in Creon, but too late. His single-mindedness has resulted in the death of both his son and his wife, thus teaching him the lesson (as the Chorus suggests as the play concludes) that law un-tempered by compassion is ultimately inhumane and destructive.