SqlException: Invalid column name 'SemesterId'. after model modified , migration and update database

public class Subject{
public int Id {get;set;}
public string Name { get; set; }
public string Code { get; set; }
public int Units {get;set;}
public string StaId { get; set; }
public string SemId{ get; set; }

//public int SemesterId{get;set;}
}

I had removed the SemesterId and after model modified , migration and update database done i am getting this error.