Finely dice onion. Cut carrot into half moons (in half lengthwise then slice horizontally). Use white and light green parts of leeks only, thoroughly clean, and cut into 1/3 inch rounds.
Heat olive oil in a pot over medium heat and add diced onion, cook until starting to soften. Add carrots and cook until starting to soften. Add leeks and stir for a couple of minutes. Add water, sugar and salt. When the water boils, add rice and lemon juice. Cook, covered, on low heat, until rice is cooked through, about 20 minutes.
This dish is best served cold, or at room temperature with a squeeze of lemon and a slice of crusty bread.
*Note: If you prefer to use brown rice, be sure it is already cooked before adding it to the dish.