As an Italian, I feel the urge to jump in here. Sugar in dough is used to kickoff/boost yeast levitation, while sugar in sauce is used to affect tomato acidity. In both cases, they are not intended to provide your pizza with a sweet taste. If for some reasons you like some sweet flavor on your pizza, you should at least take into account the fact that it comes as a byproduct of diverse chemical reactions that affect consistency and PH of your pizza in multiple/subtle ways.