What are the chances of getting a girl pregnant when shes on bc, the male uses a condom, and doesn't ejaculate inside of her?

Very unlikely: Though not impossible, the scenario you describe has a very, very, unlikely chance of resulting in a pregnancy.

Slim to none: Assuming that female takes unexpired birth control correctly & regularly w/o fail and that male wears intact condom appropriately, concurrent use of both forms of contraception make it very unlikely to get pregnant from this particular sexual event. The problem lies in that the participants may not always be so fastidious. Regardless of ejaculation inside or out, withdrawal method is not reliable.