Is Logan designed to be less sensitive to the unleaded fuel quality? (it was in advertisements, like it was designed for countries where fuel quality is not so great etc.).

And how engine behaves in case that there are some water (or other non-fuel liquids) in the fuel?

Does anyone has some practical experience?

As you probably know, the same engine from Logan was first introduced by Dacia on the Supernova model, and from my experience with Supernova the fuel quality is important. Bad quality fuel used on common basis will affect your fuel-injectors and the catalityc convertor.
If you will use bad unleaded fuel once or twice I don't think that will have a major effect on how the engine will work during its life. But again it depends on how bad the fuel is. On the romanian side of the forum, a user, Liviu, had his engine jammed due to very poor quality fuel, so don't try your luck.

The engine is pretty tolerant to bad fuel.
Is not workink as its best, but i tolerant, because is simple.