CREATE TABLE table_203_33 (id NUMBER, "conference" CLOB, "date" CLOB, "place" CLOB, "attendance" NUMBER, "archive of presentations" CLOB)

how many days was the wikimania 2011 ?
SELECT "date" - "date" FROM table_203_33 WHERE "conference" = 'wikimania 2011'
SELECT "date" - "date" FROM "table_203_33" WHERE "conference" = 'wikimania 2011'