CREATE TABLE table_name_72 (ipsos_5_16_09 VARCHAR, tns_sofres_5_28_09 VARCHAR)

Which Ipsos 5/16/09 has a TNS-Sofres 5/28/09 of 2.5%?
SELECT ipsos_5_16_09 FROM table_name_72 WHERE tns_sofres_5_28_09 = "2.5%"
SELECT "ipsos_5_16_09" FROM "table_name_72" WHERE "2.5%" = "tns_sofres_5_28_09"