Got the solution...Its working..
if (dtWebsite.Rows.Count > 0)
{
DataRow[] drWebsite = dtWebsite.Select("in_website_id in (1,604)");
int iRowIndex = 0;
foreach (DataRow drWebsite1 in drWebsite)
{
DataRow drWebsite2 = dtWebsite.NewRow();
drWebsite2.ItemArray = drWebsite[iRowIndex].ItemArray;
dtWebsite.Rows.Remove(drWebsite[iRowIndex]);
dtWebsite.Rows.InsertAt(drWebsite2, 0);
iRowIndex ++;
}
ddlWebsite.DataSource = dtWebsite;
ddlWebsite.DataTextField = "vc_website_name";
ddlWebsite.DataValueField = "in_website_id";
ddlWebsite.DataBind();
ddlWebsite.Items.Insert(0, new ListItem("Select Website", "0"));