Data type Interval in Oracle with C #

I hope you can help me with my problem which is as follows:

I have an application made in C# that connects to a database of Oracle , and in turn in this I have a table with a field INTERVAL DAY(2) TO SECOND(6)" (TIEMPOEJECUCION) when I bring all the fields in the table read all correctly except this field Interval I tried everything until I made a cast and nothing works for me, I hope you can help me.

PS: The most curious thing is that in SQL Developer if I see the information of Type Interval

Greetings!

public static Documento SelectByNUNICODOCT(long NUNICODOCT)
{
    var resultado = (Documento)null;

   using (var conexion = new OracleConnection(ConfigurationManager.ConnectionStrings["CadenaConexion"].ConnectionString))
    using (var comando = conexion.CreateCommand())
    {
        comando.CommandText = "SELECT NUNICODOCT , TIPODOCUMENTO , IDEQUIPO , NOHOJAS , NOHOJASPROC , TIEMPOEJECUCION, FECHADESCARGA , FECHAPROCESO , FECHAREGRESO , PESO  FROM APP_OCR.DOCUMENTO WHERE NUNICODOCT=:NUNICODOCT";
        comando.Parameters.Add(new OracleParameter("NUNICODOCT", NUNICODOCT));

        using (var lector = comando.ExecuteReader())
           if (lector.Read())
              resultado = Mapping(lector);

           if (conexion.State != ConnectionState.Closed)
                    conexion.Close();
     }

     return resultado;
}

private static Documento Mapping(OracleDataReader lector)
{
    var resultado = new Documento();

    resultado.NUNICODOCT = lector.GetInt64(0);
    resultado.TipoDocumento = lector.GetInt16(1);
    if (!lector.IsDBNull(2))
       resultado.IdEquipo = lector.GetInt64(2);
    if (!lector.IsDBNull(3))
       resultado.NoHojas = lector.GetInt32(3);
    if (!lector.IsDBNull(4))
       resultado.NoHojasProc = lector.GetInt32(4);
    if (!lector.IsDBNull(5)) // Esta línea siempre lleva el valor Nulo
       resultado.TiempoEjecucion = lector.GetTimeSpan(5);
    if (!lector.IsDBNull(6))
       resultado.FechaDescarga = lector.GetDateTime(6);
    if (!lector.IsDBNull(7))
       resultado.FechaProceso = lector.GetDateTime(7);
    if (!lector.IsDBNull(8))
       resultado.FechaRegreso = lector.GetDateTime(8);
    if (!lector.IsDBNull(9))
       resultado.Peso = lector.GetInt64(9);

    return resultado;
}