Kammala jumla mai zuwa: Demko ya lashe lambar azurfa a matsayin memba na kungiyar 'yan kasa da shekaru 18 na Amurka a 2013 IIHF World U18 Championships. Ya kuma kasance memba na kungiyar matasa ta Amurka a gasar
2014 IIHF World Junior Championship, kuma ya kasance madadin abokin wasan Hockey East mai tsaron gida Jon Gillies na Providence.