CREATE TABLE table_42112 ("Source" CLOB, "Date" CLOB, "Clinton" CLOB, "Obama" CLOB, "Undecided" CLOB)

When has a Source of surveyusa and a Obama of 54%?
SELECT "Date" FROM table_42112 WHERE "Source" = 'surveyusa' AND "Obama" = '54%'
SELECT "Date" FROM "table_42112" WHERE "Obama" = '54%' AND "Source" = 'surveyusa'