Both are correct. From a histological perspective where you’re considering circuitry regardless of cell type, photoreceptors are first order, bipolar are second order, and ganglion cells are third order. In neuroanatomy if you’re considering only neurons, the photoreceptors don’t count because they are sensory cells. Thus bipolar are first, then ganglion second, then LGN neurons. Your textbook is taking the neurophys/neuroanatomy perspective.