There is no defined time of how long you can hold stock. You have seen the once in a lifetime pandemic fall in nifty, which took nifty to 7500 levels. It recently touched 18500 levels, which is near 150%. In 1.5 years, nifty gave 150% returns, which is exceptional.
A long-term holding period is one year or more with no expiration. Any investments that have a holding of less than one year will be short-term holds.