I am a nurse. I have always seen Apgar scores done. If, @ 1 minute, the baby is intubated and being bagged, I would probably score 0, then evaluate for the other criteria. If the Apgar @ 5 minutes was < 6, I would repeat the scoring @ 10 mins.
I've also seen Apgars given by Delivery Room RNs, ALS RNs (in our Level 2 nursery, RNs are trained to resuscitate, intubate, place umbilical lines, etc., until the Neonatalogist and/or transport team arrive). In my previous job, a Level 3 Unit, the residents and fellows gave the score @ the deliveries they attended, otherwise, the Delivery room nurse did it.