Based on this circuit, we can see that when x is 0 and y is 1, the output o is 1.
By doing the same sort of propagation for other combinations of input values, it’s possible to build up the following table showing how this circuit behaves for different combinations of inputs:
x y o
0 0 0
0 1 1
1 0 1
1 1 0
To interpret this table, just look at the second row: it has a 0 in the x column, 1 in the y column, and 1 in the o column. This indicates that if the x input is 0 and the y input is 1, then the circuit's output o will be 1.
Enjoy...😎