You have an additional set of {} between your first if/else statement and the second one.
This should work:
void loop()
{
if (digitalRead(53) == LOW) {
digitalWrite(12, HIGH);
delay(12);
}
else {
digitalWrite(12, LOW);
delay(12);
}
if (digitalRead(49) == LOW) {
digitalWrite(10, HIGH);
delay(12);
}
else {
digitalWrite(10, LOW);
delay(12);
}
}