Some of your results will stay. SEO is like fitness. If you work out for a year, have good diet, and sleep well for a year, then don't work out for a couple months, you're going to retain a lot of the benefit. The same thing goes for SEO. If you've worked hard to get to the first page, then you stop doing any work, you're likely to remain on the first page for a month or so, but then you'll drop to the second or third page and stay around there for a longer period of time. If you neglect your website completely, then you are likely to fall even further.