When we can say 0 and 1 in digital electronic?
In digital logic circuits, 1 and 0 are labels, not physical things.  Current and voltage are physical things.  For common logic circuit like TTL and its many derivatives, a voltge in the range of 0 v to +0.8 V is called a logic 0, and a voltage in the range of 2.4 V to 5 V is called a logic 1.
In general electronic circuit discussions, electron flow rarely comes up.  Circuit power is discussed in conventional flow - current flows from + to -, from a more positive voltage to a more negative (or less positive) voltage.
Your diagram is ok for showing where energy might move from and to, but it is not a schematic.  A schematic will have a line (or line structure, like a bus) for every individual conductor, showing return paths for all currents.