Leah died some time before Jacob (according to Genesis 49:31) but we are not told exactly when. Please cite a source as to exactly when Leah died.
Seder Olam Rabba says that Leah passed away in year 2216 after creation, 9 years after Rochel, in the same year that brothers sold Yosef to Mitzrayim. Rochel died when she was 36, so Leah died when she was 45.
More precisely, this is in the 2nd chapter of Seder Olam Raba. The Vilna Gaon derives there that Leah had to pass away before Yosef was sold.
The Sefer Hadoros page 54 writes that Leah died in 2214 at 51 years of age. Or she died 2216. Others say she was 44. Some say she was born 2163, 2164 and twins, others 2170.