How does logisim differ from redstone and real life circuitry?
The first circuit you have drawn is simply short circuited. Electrically you can't drive a line both low (zero volt) and high at the same time on the same wire. The current would just flow straight from the high line down to the zero voltage. 

There are lots of examples on how to build logic gates. Like >this&lt;.
But usually it is much simpler to buy a ready made logic gate from the 7400 series.