For air travel purposes - whatever passport you plan to use for travel. In most cases they need it to determine what documentation you'll need at your destination (and that you have it) and in some cases to report ahead to the destination country's authorities. In your case Macedonian passport/national, Macedonia destination, all clear. Going back to BTS/VIE, you'll have to show your residence permit so the airline will know you're eligible to enter Schengenistan.