Seed Availability and Competition Act of 2013 - Permits a person who plants patented seed or seed derived from patented seed to retain harvested seed for replanting by such person if that person: (1) notifies the Secretary of Agriculture (USDA) of the type and quantity of seed to be retained, and (2) pays the appropriate fee established by the Secretary.

Establishes the Patented Seed Fund in the Treasury into which such fees shall be deposited and from which the Secretary shall pay appropriate fees to patent holders.

Imposes an additional duty on the imported product of exported genetically modified seed on which royalties or other fees are charged by the patent owner to purchasers of the seed in the United States and on which no fees or lesser fees are charged to purchasers of the exported seed in a foreign country. Requires that such duties be deposited in the Fund for distribution to the appropriate patent holders.