[Table("DirEmployees")]
    public class DirEmployeeLogin
    {
        [Key]
        public int? DirEmployeesID { get; set; }
        public string DirEmployeesName { get; set; }
        public string DirEmployeesLogin { get; set; }
        public string DirEmployeesPswd { get; set; }
    }

    [Table("DirEmployees")]
    public class DirEmployee
    {
        [Key]
        public int? DirEmployeesID { get; set; }
        public string DirEmployeesName { get; set; }
        public string DirEmployeesLogin { get; set; }
        public string DirEmployeesPswd { get; set; }

        //Дополнительные поля
    }

                var query =
                    (
                        from x in db.DirCustomers
                        where x.Login == "XXX" && x.Active == true
                        select new
                        {
                            DirCustomersID = x.DirCustomersID,
                            Active = x.Active
                        }
                    );

SELECT 
    [Extent1].[DirCustomersID] AS [DirCustomersID], 
    [Extent1].[Active] AS [Active]
    FROM [dbo].[DirCustomers] AS [Extent1]
    WHERE ([Extent1].[Discriminator] = N'DirCustomer') AND ([Extent1].[Login] = @p__linq__0) AND (1 = [Extent1].[Active])