CREATE TABLE table_39207 ("Isotope" TEXT, "Half-life" TEXT, "Decay mode" TEXT, "Discovery year" TEXT, "Reaction" TEXT)

What is the half-life discovered in 2003?
SELECT "Half-life" FROM table_39207 WHERE "Discovery year" = '2003'
SELECT "Half-life" FROM "table_39207" WHERE "Discovery year" = '2003'