Should someone who caught up with the Imam in the last Tashahhud on Friday complete his prayer as Dhuhr or Jumu'ah?

He completes it as Dhuhr (noon prayer) because he missed Jumu'ah (Friday prayer). If he does not catch up with at least one rak'ah (unit of prayer), then he is not considered to have caught Jumu'ah, and he should pray it as Dhuhr. If he catches someone who is making up the prayer and prays with him, he should pray Dhuhr and not Jumu'ah. It is stipulated that this must be after the zawal (midday, when the sun begins to decline), because the Dhuhr prayer is not permissible except after the zawal, by the consensus of the Muslims.