Please refer these two experments details:
1. Proved by Galileo Galilei at Pisa Tower(1583).
2. Analytical analisys, demonstration and mathematical form by Sir Isaac Newton(1675).
Both will reach at the same time, if size and shape of both are same. The initial speed is 0 for both, and the only acceleration working in that system would be g(Gravity acceleration). So, as the distance is the same, the final speed will be the same too.
The only reason which could change this result is a difference in the shape of both objects. While they fall to the ground, they must "open" a way across the air. The shape of the falling object will decide the force needed to open that way. This is called the "Air resistance". Depending on the shape of the object, the resistance force, will be bigger or smaller. As this force works counter to g, the falling time will decrease.
Between a feather and a plumb ball, the falling time will be the same in vaccum, but inside air, the resistance force for the feather has almost the same value than gravity, while for the ball, the resistance is very much weaker than gravity.
An opened and a closed parachute weights the same in both cases, but the resistance force changes a lot when it opens.
So roti will come first, if the size is smaller than pizza.