The ASX stock Washington H. Soul Pattinson and Co. Ltd (ASX: SOL) is a great option for long-term investing, in my opinion. The investment conglomerate has already proven its longevity by operating for more than 120 years.

But, there's a lot more to its appeal than just its age. I'm going to run through some of those positives in a moment, but I'm reminded of something Warren Buffett once said.

He suggested that investors should only buy shares of a company they'd be happy to own for at least a decade (or more).

I'd be very happy to own Soul Patts shares over the next decade for the following reasons.

The ASX stock is well-placed to deal with uncertainties

There are a few sizeable questions that businesses may have to deal with in the coming months and years.

I'm thinking of issues like this ongoing trade war between the US and China which may be solved in a short amount of time, or it could be a feature of the next four years (with potentially increasing painful knock-on effects).

There's also the growing capabilities of AI – what impacts will that have on certain industries?

There are plenty of things to ponder on.

For me, the diversified and defensively-minded portfolio of Soul Patts is well-positioned to deal with whatever happens next. It's invested in areas like telecommunications, resources, industrial property, swimming schools and agriculture.

Another positive is that management are willing to look across various sectors for opportunities. This allows it to diversify and future-proof its portfolio to ensure ongoing long-term growth.

Good management of capital for shareholders

To survive and thrive for a century, the ASX stock has been managed with the long-term in mind. The management and investment teams do make investments, thinking years ahead.

One of the main reasons why I'd be comfortable owning Soul Patts shares for so long is that it's not trying to take massive risks with its portfolio. On top of that, the company has rewarded long-term investors with a pleasing dividend record.

It has paid a dividend every year since it listed over 120 years and it has grown its annual ordinary dividend each year since 2000. That's the best record on the ASX.

It's not guaranteed that the company will grow its dividend every year for the next decade, but I think it's one of the most likely ASX stocks to achieve that consecutive annual dividend growth. I'm looking for businesses with that sort of ability to reward shareholders consistently.

Ultimately, I'm invested in Soul Patts shares for the business operational growth and long-term profit growth. Part of that profit growth can translate into cash returns from the business, which is what I'm hoping to see over the next decade with my investment.