name the tv show whose opening theme is margarita vargas and the subsequent work is por siempre mi amor ?
SELECT DISTINCT var_uri where brack_open var_uri dbo_openingTheme dbr_Margarita_Vargas sep_dot var_uri dbo_subsequentWork dbr_Por_siempre_mi_amor sep_dot var_uri a dbo_TelevisionShow brack_close