Preheat oven to 325 degrees F (165 degrees C). Grease and flour a 10 inch Bundt pan.
In a large bowl, cream together the butter, shortening and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the vanilla and lemon extracts. Beat in the flour alternately with the lemon-lime soda, mixing just until incorporated.
Pour batter into prepared pan. Bake in the preheated oven for 70 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool on a cake rack for 30 minutes before removing from the pan.