table
If I write query to fetch City column values:

  1. public JsonResult getEmpCity()
  2. {
  3. using (CompanyDBEntities dc = new CompanyDBEntities())
  4. {
  5. var query = (from p in dc.Emp_Information
  6. select p.City).ToList();
  7. return new JsonResult
  8. {
  9. Data = query.ToList(),
  10. JsonRequestBehavior = JsonRequestBehavior.AllowGet
  11. };
  12. }
  13. }
Debug this call and see result.

result

Now write your code like below:
  1. public JsonResult getEmpCity()
  2. {
  3. using (CompanyDBEntities dc = new CompanyDBEntities())
  4. {
  5. var query = (from p in dc.Emp_Information
  6. select p.City).Distinct().ToList();
  7. return new JsonResult
  8. {
  9. Data = query.ToList(),
  10. JsonRequestBehavior = JsonRequestBehavior.AllowGet
  11. };
  12. }
  13. }
And See result.

result