Amongst other things Leo represents glamour, theatre, romance, love affairs, children, sporting events and speculative investments. Saturn in Leo may cast a more serious pall on some of these areas of life over the next two year period, but more so on the global scale of consciousness and not necessarily for most individuals.
When it comes to transits of the outer planets (including Jupiter, Saturn, Uranus, Neptune and Pluto) the sign the planet is transiting through is not nearly as relevant as the house it represents in your chart. It is much more helpful to see which house is affected in your chart by Saturn's transit in order to interpret what area of your life may be more infused with increased responsibility, seriousness and karma as Saturn transits this house.
Ebertin's book description of Saturn in Leo or in fifth house is "reliability, loyalty, simplicity, inhibitions with regard to social contacts, dislike of formalities, shyness, caution, diplomacy and inhibited sex-expression."
Here's an excerpt from Marielle Croft's excellent article about Saturn in Leo:
Aquarius had Saturn in their sign from February 1991 to February 1994. For them this is “half way” into Saturn’s 29-30 year cycle. It is their time of climax when they can see in full light the result of what they have started then. This is a time of much awakening and maturity when they can reap the rewards of the experience acquired along the way. Now they understand better the value of pushing and working when if feels right, and to detach and let go when it is not fulfilling. Either they enjoy success or failure at this time, their priceless gift remains “experience!”, not only on the physical level of reality but also in the acquisition of self-knowledge. If they are facing success then there is great fertility in their projects; they can grow “branches” and expand meaningfully the themes of their journey.
See also an article about Saturn transits here at Aquarian Digest.
The above fine art print is "Sophisticated Saturn" by Sloan-Mcg