Can't find a table 0 in ASP .NET

private DataTable deleteSession(string userSession, string mode)
        {
            DataSet dsData1 = new DataSet();
            SqlConnection sqlCon;
            SqlDataAdapter sqlCmd;

            try
            {
                using (sqlCon = new SqlConnection(ConfigurationManager.ConnectionStrings["conString"].ConnectionString))
                {
                    sqlCmd = new SqlDataAdapter("USP_UserLogin", sqlCon);
                    sqlCmd.SelectCommand.CommandType = CommandType.StoredProcedure;
                    sqlCmd.SelectCommand.Parameters.AddWithValue("@loginID",userSession);
                    sqlCmd.SelectCommand.Parameters.AddWithValue("@password", string.Empty);
                    sqlCmd.SelectCommand.Parameters.AddWithValue("@sessionID", string.Empty);
                    sqlCmd.SelectCommand.Parameters.AddWithValue("@mode", mode);
                    sqlCon.Open();
                    sqlCmd.Fill(dsData1);
                    sqlCon.Close();
                }
            }
            catch
            {
                throw;
            }
            return dsData1.Tables[0];
        }

       

        protected void hnkLogOut_Click(object sender, EventArgs e)
        {
            deleteSession(Convert.ToString(Session["UserID"]), "LOGOUT");
            Session.Abandon();
           // Server.Transfer("~/Login.aspx");
            Response.Redirect("Login.aspx?mode=logout");
        }

IF @mode = 'LOGOUT'
BEGIN

	UPDATE [Users]
	SET IsLogin = 0 ,
		userSession = '' 
	WHERE LoginID = @loginID 
          SELECT 0
END

IF @mode = 'CHANGELOGIN'
BEGIN
	UPDATE [Users]
	SET IsLogin = 1 ,
		userSession = @sessionID ,
		LastLogin = GETDATE() 
	WHERE LoginID = @loginID 
	SELECT 1
END