Found Levchenko Natalia Tarasovna in Kryvyi Rih, born 1912. I do not believe that she would still be living. She is not listed in the phone directory. Below is her address.
Левченко Наталия Тарасовна
Гірничий 13 - 103
Кривий Ріг місто
NOTE: Three different ways in spelling the name of the street. I found the street name Гірничий in the address data; Гірницький (мкрн), in the postal code data; Горняцкий Мкрн in the phone directory. It took me some time to figure all this out! Some data is in Ukrainian and some in Russian.
Yes, there are Levchenko (Левченко) in Medvyn (Медвин).