Nehemiah 7 - Ezra 2

There are some discrepancies with names and numbers in these chapters, but Jamieson-Fausset-Brown gives a good answer.

"But the discrepancy is sufficiently accounted for from the different circumstances in which the two registers were taken; that of Ezra having been made up at Babylon, while that of Nehemiah was drawn out in Judea, after the walls of Jerusalem had been rebuilt. The lapse of so many years might well be expected to make a difference appear in the catalogue, through death or other causes; in particular, one person being, according to Jewish custom, called by different names."-Jamieson-Fausset-Brown Bible Commentary