In which small cap fund shall I invest for a long term (10 years or more): reliance, Franklin India smaller co., or L&t emerging business?

Go for two out of the three you mentioned. All have done well at various periods of time, and the best strategy is to invest in two and then based on how things pan out, change the selection after a thorough annual review (with help of an advisor if possible).

I would perhaps suggest Franklin India Smaller Companies and L&T Emerging Business as of now for a combination of patience and aggression.