You would be eligible for gratuity as you have worked in college since June 2008 .you are at liberty to resign after maternity leave
2) If "leave without pay" has been duly sanctioned, it entails that the period is concerned as service and there will be no adverse consequences. "Loss of pay" pay signifies unauthorized absence entailing break in service with all its adverse consequences unless the period is got regularised
3) under the provisions of Payment of Gratuity Act, continous service includes all kinds of leave unless by an express order there is break in service. .