Entity Framework always adds two records in the tables - entity-framework

Question

I'm implementing an ASP.NET Core 3.1 app. I have implemented following code to insert record in SQL Server database via EF Core but each time I save data, it inserts two records in PersonRequester and Requester table. I appreciate if anyone suggests me how I can prevent reinserting records.
Requester ap = new Requester();
ap.Address = RequesterViewModel.Requestervm.Address;
ap.RequesterType = RequesterViewModel.Requestervm.RequesterType;
ap.Description = RequesterViewModel.Requestervm.Description;
ap.Name = RequesterViewModel.Requestervm.Name;
var pa = new PersonRequester()
{
BirthCertificateNo = RequesterViewModel.personRequestervm.BirthCertificateNo,
IssuePlace = RequesterViewModel.personRequestervm.IssuePlace,
NationalCode = RequesterViewModel.personRequestervm.NationalCode,
Requester = ap
};
using (var context = new DBContext())
{
context.PersonRequester.Attach(pa);
try
{
context.SaveChanges();
}
catch (Exception e)
{
throw e;
}
}
public partial class Requester
{
public Requester()
{
PersonRequester = new HashSet<PersonRequester>();
}
public int RequesterId { get; set; }
public int RequesterType { get; set; }
public string Address { get; set; }
public string Description { get; set; }
public string Name { get; set; }
public virtual EntityType RequesterTypeNavigation { get; set; }
public virtual ICollection<PersonRequester> PersonRequester { get; set; }
}
public partial class PersonRequester
{
public int RequesterId { get; set; }
[DatabaseGenerated(DatabaseGeneratedOption.Computed)]
public int RequesterType { get; set; }
public string NationalCode { get; set; }
public string BirthCertificateNo { get; set; }
public string IssuePlace { get; set; }
public virtual Requester Requester { get; set; }
public virtual EntityType RequesterTypeNavigation { get; set; }
}