in this selectlist all the id's display in dropdown list. i need whowever login in this application that login id how to get it

public ViewResult Index()
        {
            var ded_table = db.ded_table.Include("login_user");
            return View(ded_table.ToList());
        }  

[HttpPost]
        public ActionResult Create(ded_table ded_table)
        {
            if (ModelState.IsValid)
            {
                db.ded_table.AddObject(ded_table);
                db.SaveChanges();
                return RedirectToAction("Index");  
            }

            ViewBag.ded_emp_id = new SelectList(db.login_user, "EmpId", "FirstName", ded_table.ded_emp_id);
            return View(ded_table);
        }