Gorgorab, probably. Or Seeker. Mausoleum Mage, Kaiden, Apothecary would also make sense afterwards. 

I would go with Gorgorab as well all the other champions mentionned above should go to 60 eventually.

First, stop leveling that 5* Incubus that is at 32 😂

I would say Apo as he can help in all areas of the game, but I do not have Gorgo, Mage, or Seeker. I wish I did, as I hate seeing all three in Arena, and can understand if one of those had higher priority over Apo.

Seeker is a monster geared high speed/acc/HP.  I use mine in arena since his provoke messes us the other teams turn. And now the dragon in doom tower has a provoke weakness I use him there aswell.

Other than that, what the others said!

gorgo

Thnx for the advice...

What composition could i use to do dragon or ice golem?

You need a poisoner for dragon  & golem (and CB) eventually.  Dragon 20 should be your first goal, looks like you are progressing well. I don't see a top teir poison on your roster, so u may actually end up using Kael (far more useful than Elhain unfortunately, I made same mistake with starter lol).

I would think Apo, Gorg, Maus Mage, Kael plus ???? hopefully you pull something good today for dragon and golem.  Progressing with 100% win rate is more important than how fast you can beat the stage.  You need better gear from dragon to progress further in dragon...