Preheat oven to 350 degrees F (175 degrees C). Grease a 5x9-inch loaf pan.
Mix cornmeal, buttermilk, flour, sugar, vegetable oil, salt, and baking soda in a bowl until thoroughly combined.
Pour batter into prepared loaf pan.
Bake in the preheated oven until top is golden brown and a toothpick inserted into the center of the loaf comes out clean or with moist crumbs, about 1 hour.