Jagiellonia BiaÅ ystok is a Polish football club , based in BiaÅ ystok , that plays in Ekstraklasa league at the BiaÅ ystok City Stadium . Jagiellonia BiaÅ ystok is a Polish football club , based in BiaÅ ystok , in the Ekstraklasa League that plays at the BiaÅ ystok City Stadium .