The term translated as escaped
refers to persons who got away from some danger and found a place of safety. The challenging question is whether this refers to (the descendants of) Jews who were left behind in Judah years ago when the exile first occurred (in the years 603 to 587; 2 Kings 25:1–30) or whether this refers to Jews who escaped Babylon with the returns under Sheshbazzar or Ezra as mentioned in Ezra 2:1–70 and Ezra 7:1–28. Of course, there could be a third option, that is, both groups. Nehemiah’s further formulation of his question indicates that the third option is correct.
2 that Hanani, one of my brothers, came with certain men from Judah. And I asked them concerning the Jews who escaped, who had survived the exile, and concerning Jerusalem.