It depends, if you put a male tiger against a male lion, the chances of the lion winning gets higher.
Not because the lion is stronger than a tiger but because of its mane. Tigers almost all the time, go for the neck. As they are solitary hunters, it is always reasonable for them to go for the neck so that they can kill easily. So this behaviour gives the tiger a disadvantage. Cause lions mane is thick so it gets in the way of the bite of the tiger. So it takes more bites for the tiger to take down a tiger. Tigers are very quick fighters and weigh more, so they exhaust their energy quickly compared to lions. As lions are not as aggressive as tigers and use one claw at a time, they save their energy more. So if it is a male lion vs a tiger, then the tiger is in trouble, it should tweak its strategy a little bit. And since lions hunt in pride, they go for a bite on any vulnerable regions on the body. Neck, abdomen, legs or anything that they can bite on to weaken the pray. By the time the tiger gets hold of a lion's neck, it will already be weakened a lot. So the scales tip towards the lion a little bit. Not saying a lion would win definitely but just saying chances get higher for the male lion.
Coming to a tiger vs female lions. Almost all the time the tiger wins.