Top left....NAND action....only shows zero volts at output there when both input sources are on.
Bottom left....NOR action ...inverted to OR out from the single mosfet on its right.
Right.... The lamp comes on only when both mosfets there receive a 12v input at their gates.
Final result for the LED load to turn on is XOR .... lamp on with either initial input but not with both.
7 standard N-Mosfets total.
No Rds utilised for this description...ask if you would like detail for that; Each mosfet VTO = 3v .... Total quiescent current <1mA at all times).....There are easier and other ways to do this...here is just one option using standard N-mosfets.
See my comments here for more mosfet details http://everycircuit.com/circuit/6076454007996416
Notice that creating mosfet XOR is a lot more complex than creating most other mosfet gates, such as the NOR at the bottom left of the schematic.
