Who would take over if a totalitarian dictator was assassinated?

The various powerful and rival factions come together and agree upon a person acceptable to all. Usually a person perceived as a safe non-entity that each group imagines they can control.

This method failed miserably in Germany, leading to Hitler. However, the Russians in their communist phase got it down to an exact science, in which they hardly ever had to kill too many people during the changeover.

Towards the end of the Soviet era, it got so that they could just retire their "leaders" to rest homes, a somewhat large improvement from the random ditches and dumpsters that had served originally.