As an AI language model, I do not have real-time data or the ability to predict the future. Therefore, I cannot provide the specific ranking or details about the most challenging humanitarian crises in 2023. The ranking of humanitarian crises can vary depending on various factors, including conflicts, natural disasters, and socio-economic conditions. It is recommended to refer to reliable sources, such as humanitarian organizations or news outlets, for the most up-to-date information on current and future crises.