Validating Duplicate Email Id from Database while Form Filling

Create proc [dbo].[sp_InsPersonInfo]
@pName varchar(50),
@pEmail varchar(80)
as
declare @Count as int
set @Count=(select count(id) from Persons where PersonEmail=@pEmail)
select @Count as DuplicateEmail
if @Count=0
begin
insert into Persons values(@pName,@pEmail)
end

 public DataSet Insert(string pName,string pEmail)
    {
        cnn = new SqlConnection(Conn);
        cmd = new SqlCommand("sp_InsPersonInfo", cnn);
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@pName", pName);
        cmd.Parameters.AddWithValue("@pEmail", pEmail);
        ada = new SqlDataAdapter(cmd);
        ds = new DataSet();
        ada.Fill(ds);
        return ds;
    }
Submit_Click()
{
    DAL = new PersonDATAlayer();
        ds = new DataSet();
        ds=BAL.Insert(txtName.Text,txtEmail.text)
        int Count;
        Count = Convert.ToInt32(ds.Tables[0].Rows[0]["DuplicateEmail"].ToString());
        if (Count > 0)
        {
            string strjscript = "<script language='javascript'>alert('Email id already exists ');</script>";
            Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "myscript", strjscript);
        }
 }