CREATE TABLE table_name_26 (ipsos_5_25_09 VARCHAR(255), tns_sofres_5_28_09 VARCHAR(255))
Which Ipsos 5/25/09 has a TNS-Sofres 5/28/09 of 20%?
    
SQL: SELECT ipsos_5_25_09 FROM table_name_26 WHERE tns_sofres_5_28_09 = "20%"