I never took a physics class. I'm going to consider putting that on my list of things to do.
We can help you but you need to help yourself by doing some research. There' s literally thousands of links explaining relays and leds. You could at least Google the subject see what a DPDT relay is.
Can you explain the difference in using a double pole, and putting the led in parallel with the relay? To my understanding a double pole would have two gates. They would both "energize" at the same time, but one pole would connect the circuit to the dangerous tinkering objective that I want to know if is hot, the other pole would connect the circuit to the led, but the led could still burn out and I would never know until I met the bad news bears.
Relays don't have gates, and a Double Pole Double Throw relay only has one coil. Relays have
contacts and the two sets (three each) are not connected to each other. If you want to know if the relay is energized, just put a low resistance resistor in series with the coil and measure the
voltage drop across the resistor using analog inputs. Please make a little effort to research your topic before asking questions. You could have learned all of this with one Google search in the
time it took me to type this post.