Usually, cricket matches last up to 5 days and can end in a win, loss, draw, or tie. However, back in 1939, they played what was called a "timeless Test." In these special matches, there was no time limit, so the game kept going until one team won.
That's why the match between England and South Africa continued for 12 days without stopping in Durban, South Africa. It wasn't called a draw because they wanted to have a clear winner. Eventually, they had to stop playing because the English team needed to catch their boat home. So, after all that time, the match ended without a winner anyway!
Below is the link for the scorecard of the match :-
https://www.espncricinfo.com/series/england-tour-of-south-africa-1938-39-61688/south-africa-vs-england-5th-test-62657/full-scorecard