Sec. 2.03.  DEFENSE.  (a)  A defense to prosecution for an offense in this code is so labeled by the phrase:  "It is a defense to prosecution . . . ."
(b)  The prosecuting attorney is not required to negate the existence of a defense in the accusation charging commission of the offense.
(c)  The issue of the existence of a defense is not submitted to the jury unless evidence is admitted supporting the defense.
(d)  If the issue of the existence of a defense is submitted to the jury, the court shall charge that a reasonable doubt on the issue requires that the defendant be acquitted.
(e)  A ground of defense in a penal law that is not plainly labeled in accordance with this chapter has the procedural and evidentiary consequences of a defense.
Acts 1973, 63rd Leg., p. 883, ch. 399, Sec. 1, eff. Jan. 1, 1974.  Amended by Acts 1993, 73rd Leg., ch. 900, Sec. 1.01, eff. Sept. 1, 1994.