Getting column value - Bad vs. Good Linq to Sql

Bad
int mainDepID = db.Departments.SingleOrDefault(y => y.ID == depID).MainDepartmentID;

Good
int mainDepID = 0;

Web.Model.Department currentDepartment = db.Departments.SingleOrDefault(y => y.ID == depID);

if (currentDepartment != null)
{
   mainDepID = currentDepartment.MainDepartmentID;
}