Rubuta ci gaba don wannan sakin layi - Demko ya lashe lambar azurfa a matsayin memba na ƙungiyar 'yan ƙasa na Amurka a karkashin 18 a 2013 IIHF World U18 Championships. Ya kuma kasance memba na kungiyar matasa ta Amurka a gasar zakarun duniya ta IIHF ta 2014
, kuma ya kasance madadin abokin wasan Hockey East mai tsaron gida Jon Gillies na Providence.