I use this expression for my latest view and it seems to work as it should
episode<;><Episode.FirstAired>;<=;<today><cond><Episode.FirstAired>;>=;<today-30><cond><Episode.Watched>;=;0<;><Episode.FirstAired>;desc<;>
Sweden
Sweden
episode<;><Episode.FirstAired>;<=;<today><cond><Episode.FirstAired>;>;1900-01-01<cond><Episode.Watched>;=;0<;><Episode.FirstAired>;asc<;>