I wonder if you mean Lemberg, now L'viv in Western Ukraine - it had a large Polish population up to WW2.
In the right contexts, you can get an approximation of an "am" sound in Polish using the vowels ą or ę, so if you don't think L'viv is worth considering you might look for places beginning Ląb- or Lęb- (or Łąb- or Łęb-) - personally, though, I would want to look at L'viv first.