Calling up the Chassan-Torah/Chassan-Bereishis

What is the nusach for calling up the chassan Torah and chassan Bereishis ? In most Ashkenazi communities (Minhog Polin, chassidim) a long Aramaic reshus is recited, typically in the Polish Akdomus melody (the same as the kiddush melody for yontif).

What is done in Ashkenaz, both according the the Rishonim and the Divrei Kehillos (if they differ) ?