Neb. Rev. Stat. §§ 17-303
The mayor and city council shall, within ninety days after the declaration of the Secretary of State under section 17-301, divide the city into not less than two nor more than six wards as may be provided by ordinance. Such wards shall contain, as nearly as practicable, an equal area and an equal number of legal voters. The division and boundaries of such wards, as defined by ordinance, shall take effect on the first day of the first succeeding municipal year following the next general city election after such reorganization. Any city council member whose term continues, by reason of his or her prior election under the statutes governing cities of the first class, through another year or years beyond the date of the reorganization as a city of the second class shall continue to hold his or her office as city council member from the ward in which he or she is a resident as if elected for the same term under the statutes governing cities of the second class.
Neb. Rev. Stat. §§ 17-303