CREATE TABLE table_20931 ("Antibody" CLOB, "Brand name" CLOB, "Approval date" FLOAT, "Type" CLOB, "Target" CLOB, "Approved treatment ( s ) " CLOB)

What is the target with an approval date of 2006?
SELECT "Target" FROM table_20931 WHERE "Approval date" = '2006'
SELECT "Target" FROM "table_20931" WHERE "Approval date" = '2006'